/CTCP ((target) ((command) is implemented in nearly every IRC client. For those that it isn't, usually commands like /version ((target), /ping
((target), etc., are. The exception to this is PING, which is usually done by /ping ((target) (or /cping ((target) in ircle).

Most servers are set up to allow you receive more data than you can send; therefore some commands such as CLIENTINFO can be used to disconnect you.

The command to make your client reply to a CLIENTINFO is 12 characters (plus source/target information), while the reply to CLIENTINFO may be 100 - 200 characters. You will be disconnected with the message "Excess Flood."

DCC is started by a CTCP command. However, once it is started, it is conducted totally independant of the IRC server. For example, to
start a DCC chat connection, the originator of the request (whoever typed /dcc chat ((nick)] will send something like this:

PRIVMSG ((target) :^ADCC CHAT ((type) ((longip) ((port)^A

^A = ASCII Character 1
type = Either Chat or Talk, but almost always Chat these days
longip = 32-bit Internet address of originator's machine
port = Port on which the originator is waitng for a DCC chat

From this, their IRC client would know that the machine with address 3406736986 is ready to accept a DCC chat connection on port 2094. The IRC client of the target of the DCC chat would then establish a connection to port 2094 of machine 3406736986 if the DCC chat was accepted.

DCC file sends are similar to DCC chat requests, but follow the format below:

Where - ^A = ASCII Character 1
- filename = Name of file being sent
- longip = 32-bit Internet address of originator's machine
- port = Port on which the originator is waiitng for a DCC chat
- filesize = Size of file being sent

From this, their IRC client would know that the machine with address 3406736986 is ready to send a file named "CTCP_and_DCC" that is 4509 bytes long on port 2097. The IRC client of the target of the DCC send would then establish a connection to port 2097 of machine 3406736986 if the DCC send was accepted.